Vessels are commonly treated to reduce or eliminate narrowings caused by arteriosclerotic disease. Interventional treatments can include balloon angioplasty, stenting, drug eluting stenting, thrombectomy, atherectomy, and other procedures. During treatment particulate debris can be generated at the treatment site. Infarcts, strokes, and other major or minor adverse events are caused when debris embolizes into vasculature distal to the treatment site.
To prevent embolization of debris, embolic protection devices have been developed. During a procedure such devices can be placed distal to or proximal to the treatment site. Embolic protection devices can remove emboli from the bloodstream by filtering debris from blood, by occluding blood flow followed by aspiration of debris, or can cause blood flow reversal to effect removal of debris. The shape, length and other characteristics of an embolic protection device are typically chosen based on the anatomical characteristics in the vicinity of the treatment site.
Embolic protection devices are often delivered to and recovered from a treatment site in a patient's vessel by using catheters. In general, catheters in use can have a fixed wire (FW) configuration, an over-the-wire (OTW) configuration, or a rapid exchange (RX) configuration. FW configured catheters are used by pre-loading the embolic protection device into the catheter and advancing the assembly across a treatment site. While fewer steps are needed to use a fixed wire system they have larger crossing profiles and are less navigable than other systems through tortuous vessels. OTW configured catheters have a lumen that admits a wire therethrough and the lumen extends over substantially the entire length of the catheter. While OTW systems offer great support when trying to pass the catheter across tight lesions, the wire required must be more than twice as long as the catheter. OTW guidewires can be as long as 320 cm and it is cumbersome to handle wires of this length in a sterile field. RX configured catheters have a lumen that admits a wire therethrough but the lumen extends over a short distal length of the catheter. RX guidewires (typically 175 cm long) are easier and faster to use by one person, however RX systems do not offer the support offered by OTW systems.
In addition to the above issues discussed for FW, OTW, and RX catheters, some doctors prefer to have an option to sometimes cross a treatment site with a conventional guidewire before crossing the site with an embolic protection device. This alternate method allows a familiar guidewire, with characteristics appropriate for crossing a lesion or appropriate for support of subsequently inserted devices, to successfully cross a treatment site before opening the package of an embolic protection device. This approach avoids the cost of an embolic protection device in the event that the lesion cannot be crossed. Doctors also prefer to use certain guidewires due to their handling characteristics which are generally superior to those of the wire in an embolic protection device.
Accordingly, a need exists for an improved rapid exchange catheter for delivery and/or recovery of embolic protection devices.